Singing contest shows are unquestionably popular, but the artists whose careers they help launch tend to fall squarely on the "pop" end of the musical spectrum -- a state of affairs the shows tend to try and rectify once or twice a season by putting the singers through their paces with less predictable material. It's a noble effort, but you never know what you're going to get. Case in point: the recent episode of 'The Voice' that found contestants covering tracks by Nirvana and Foster the People.

'Voice' coach Blake Shelton didn't go too far out on a limb when he arranged for Lex Land and Charlotte Sometimes to duet on Foster the People's enormous hit 'Pumped Up Kicks' -- its lyrics may be violent, but its arrangement is smooth and catchy enough for AC radio. Aided by input from Miranda Lambert and Kelly Clarkson, the duo put their spin on the song, trading verses in the hopes of advancing to the next round. But someone had to go home, and it ended up being Land. Take a look at the clip below and see if you agree with the decision.

Meanwhile, Shelton's fellow coach Christina Aguilera paired contestants Lindsey Pavao and Lee Koch in an unexpected run-through of Nirvana's 'Heart-Shaped Box.' If you're surprised by that choice, Koch knows how you feel -- he was visibly unprepared for the performance, commenting that it had been awhile since he'd even heard the original. Unfortunately for Koch, his unfamiliarity with the material showed, and he was sent packing by a dissatisfied Aguilera. Was she justified? Watch the clip and see for yourself.

Lex Land and Charlotte Sometimes perform 'Pumped Up Kicks'

Lindsey Pavao and Lee Koch perform 'Heart-Shaped Box'